U.S. patent application number 13/688536 was filed with the patent office on 2013-06-27 for method and system for regulated exhaust heating of a charcoal canister of an emissions system to reduce heel.
This patent application is currently assigned to CONTINENTAL AUTOMOTIVE SYSTEMS, INC.. The applicant listed for this patent is CONTINENTAL AUTOMOTIVE SYSTEMS, INC.. Invention is credited to David William Balsdon, Adrian Ovidiu Crisan, Brian Gordon Woods.
Application Number | 20130160746 13/688536 |
Document ID | / |
Family ID | 47505295 |
Filed Date | 2013-06-27 |
United States Patent
Application |
20130160746 |
Kind Code |
A1 |
Woods; Brian Gordon ; et
al. |
June 27, 2013 |
Method And System For Regulated Exhaust Heating Of A Charcoal
Canister Of An Emissions System To Reduce Heel
Abstract
A evaporative emission control system includes a fuel tank,
canister communicating with the fuel tank, air intake structure
directing air to an internal combustion engine, a purge valve
connected between the canister and the air intake structure, a vent
valve associated with a source of ambient air, mixing structure
associated with vent valve to selectively receive the ambient air
that passes through the vent valve, a feed line connected between
an exhaust flow path associated with the engine and the mixing
structure, an output air flow from the mixing structure being
received by the canister, and an exhaust valve in the feed line for
controlling pressurized exhaust air flow, from the exhaust flow
path, to the mixing structure. The exhaust air flow is mixed with
the ambient air in the mixing structure with the output air flow
therefrom purging the canister of hydrocarbons to be consumed by
the engine.
Inventors: |
Woods; Brian Gordon;
(Chatham, CA) ; Balsdon; David William; (Chatham,
CA) ; Crisan; Adrian Ovidiu; (Chatham, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CONTINENTAL AUTOMOTIVE SYSTEMS, INC.; |
Auburn Hills |
MI |
US |
|
|
Assignee: |
CONTINENTAL AUTOMOTIVE SYSTEMS,
INC.
Auburn Hills
MI
|
Family ID: |
47505295 |
Appl. No.: |
13/688536 |
Filed: |
November 29, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61578510 |
Dec 21, 2011 |
|
|
|
Current U.S.
Class: |
123/521 |
Current CPC
Class: |
F02M 25/0836 20130101;
F02M 25/089 20130101; F02M 2025/0881 20130101; F02M 26/36
20160201 |
Class at
Publication: |
123/521 |
International
Class: |
F02M 33/06 20060101
F02M033/06 |
Claims
1. An evaporative emission control system for a vehicle comprising:
a fuel tank, a vapor collection canister in communication with the
fuel tank, air intake structure directing air to an internal
combustion engine of the vehicle, a purge valve connected between
the canister and the air intake structure, a vent valve associated
with a source of ambient air, mixing structure associated with vent
valve to selectively receive the ambient air that passes through
the vent valve, a feed line connected between an exhaust flow path
associated with the engine and the mixing structure, an output air
flow from the mixing structure being received by the canister, and
an exhaust valve in the feed line for controlling pressurized
exhaust air flow, from the exhaust flow path, to the mixing
structure, wherein, under certain operating conditions, the exhaust
air flow is received by the mixing structure along with the ambient
air received through the vent valve, with the output air flow from
the mixing structure purging the canister of hydrocarbons through
the purge valve to be consumed by the engine.
2. The system of claim 1, further comprising a tank isolation valve
between the tank and the canister constructed and arranged to
prevent vapors from returning to the tank.
3. The system of claim 1, wherein the air intake structure is a
turbocharger.
4. The system of claim 1, wherein the air intake structure is an
intake manifold associated with the engine.
5. The system of claim 1, further comprising a filter for filtering
ambient air prior to being received by the vent valve.
6. The system of claim 1, wherein the vapor collection canister is
a charcoal vapor collection canister.
7. A method of purging hydrocarbons from an evaporative emission
control system of a vehicle, the control system including a fuel
tank, a vapor collection canister in communication with the fuel
tank, air intake structure directing air to an internal combustion
engine of the vehicle, and a purge valve connected between the
canister and the air intake structure, the method comprising the
steps of: ensuring that pressured exhaust air flow from an exhaust
flow path associated with the engine can be received by the
canister, and selectively supplying the pressurized exhaust air
flow to the canister to purge hydrocarbons from the canister
through the purge valve to be consumed by the engine.
8. The method of claim 7, further comprising mixing the pressurized
exhaust air flow that is at a temperature above ambient
temperature, with ambient air prior to the supplying step so that a
mixture of the exhaust air flow and the ambient air is supplied to
the canister.
9. The method of claim 7, wherein a mixing structure is provided
upstream of the canister and the mixing step occurs in the mixing
structure.
10. The method of claim 7, wherein the air intake structure is a
turbocharger and the supplying step can occur during operation of
the turbocharger.
11. The method of claim 7, wherein the air intake structure is an
intake manifold associated with the engine, and the supplying step
can occur even when no vacuum can be obtained by the intake
manifold.
12. The method of claim 8, wherein the air intake structure is a
turbocharger and the supplying step can occur during operation of
the turbocharger.
13. The method of claim 8, wherein the air intake structure is an
intake manifold associated with the engine, and the supplying step
can occur even when no vacuum can be obtained by the intake
manifold.
Description
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/578,510, filed on Dec. 21, 2011.
FIELD
[0002] This invention relates to vapor management systems of
vehicles and, more particularly, to a system that allows cleaning
of a charcoal canister with heated, pressurized exhaust air.
BACKGROUND
[0003] FIG. 1 shows a conventional evaporative emission control
system (EVAP), generally indicated at 10, of a motor vehicle
including a fuel vapor collection canister (e.g., a carbon
canister) 12 and a normally closed canister purge valve 14
connected between a fuel tank 16 and an intake manifold 18 of an
internal combustion engine 20 in a known fashion. A normally open
canister vent valve 22 is in fluid communication between a vapor
collection canister 12 and ambient atmospheric conditions via a
filter 24. Under certain conditions, the purge valve 14 is opened
to direct hydrocarbon vapors to the intake manifold 18 to be
consumed by the engine 20.
[0004] After the canister 12 is purged, there is a certain amount
of hydrocarbons that cannot be removed by flowing air at ambient
temperature to purge the canister 12 completely. These residual
hydrocarbons are known as the "heel", which reduce the storage
capacity of the canister 12.
[0005] On turbocharged engines, the manifold is under pressure much
of the operating time and therefore cannot pull these hydrocarbons
from the canister 12. Some engines do not have enough time without
turbocharger operation to allow sufficient canister cleaning when
manifold vacuum is available. Many conventional engine technologies
result in significant reduced manifold vacuum which cannot purge
the heel.
[0006] Thus, there is a need in an evaporative emission control
system to clean the canister by removing the heel.
SUMMARY
[0007] An object of the invention is to fulfill the need referred
to above. In accordance with the principles of an embodiment, this
objective is achieved by an evaporative emission control system for
a vehicle. The system includes a fuel tank, a vapor collection
canister in communication with the fuel tank, air intake structure
directing air to an internal combustion engine of the vehicle, a
purge valve connected between the canister and the air intake
structure, a vent valve associated with a source of ambient air,
mixing structure associated with vent valve to selectively receive
the ambient air that passes through the vent valve, a feed line
connected between an exhaust flow path associated with the engine
and the mixing structure, with an output air flow from the mixing
structure being received by the canister, and an exhaust valve in
the feed line for controlling pressurized exhaust air flow, from
the exhaust flow path, to the mixing structure. Under certain
operating conditions, the exhaust air flow is received by the
mixing structure along with ambient air received through the vent
valve, with the output air flow from the mixing structure purging
the canister of hydrocarbons through the purge valve to be consumed
by the engine.
[0008] In accordance with another aspect of an embodiment, a method
purges hydrocarbons from an evaporative emission control system of
a vehicle. The control system includes a fuel tank, a vapor
collection canister in communication with the fuel tank, air intake
structure directing air to an internal combustion engine of the
vehicle, and a purge valve connected between the canister and the
air intake structure. The method ensures that pressured exhaust air
flow from an exhaust flow path associated with the engine can be
received by the canister. The pressurized exhaust air flow is
selectively supplied to the canister to purge hydrocarbons from the
canister through the purge valve to be consumed by the engine.
[0009] Other objects, features and characteristics of the present
invention, as well as the methods of operation and the functions of
the related elements of the structure, the combination of parts and
economics of manufacture will become more apparent upon
consideration of the following detailed description and appended
claims with reference to the accompanying drawings, all of which
form a part of this specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The invention will be better understood from the following
detailed description of the preferred embodiments thereof, taken in
conjunction with the accompanying drawings, in which:
[0011] FIG. 1 is a schematic illustration showing a conventional
evaporative emission control system.
[0012] FIG. 2 is a schematic view of an evaporative emission
control system that permits cleaning of the canister with pressure
from exhaust air flow at a temperature above ambient temperature,
according to an embodiment of the present invention.
DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT
[0013] Referring to FIG. 2, an evaporative emission control system
for a vehicle is shown, generally indicated at 26, in accordance
with an embodiment. The system 26 comprises a fuel tank 16, a
charcoal vapor collection canister 12 in communication with the
tank 16, a tank isolation valve 27 between the canister 12 and tank
16 to prevent vapors from returning to the tank, air intake
structure 28 directing air to an internal combustion engine 20', a
normally closed purge valve 14 between the canister 12 and the air
intake structure 28, an exhaust flow path 30 receiving exhaust air
flow 38 from the engine 20', and a vent valve 22 and filter 24 for
controlling flow of ambient air to a particulate separator and flow
mixing structure 32. A purging output air flow 33 of the mixing
structure 32 is received by the canister 12. An exhaust valve 34 is
provided in a feed line 36 between the exhaust flow path 30 and the
mixing structure 32. The valve 34 is constructed and arranged to
reduce pressure of the exhaust air flow 38 and controls the exhaust
air flow 38 into the mixing structure 32 and thus the canister 12.
The mixing structure 32 controls temperature of purge air flow 33
into the canister 12 by selectively mixing the exhaust air flow 38
with the ambient air that is received from vent valve 22.
[0014] In the embodiment, the air intake structure 28 is a
conventional turbocharger, but if no turbocharger is provided, it
can be the engine intake manifold 18' as a vacuum source.
[0015] Thus, under certain operating conditions (e.g., when the
canister 12 is deemed to need purging) and when valve 34 is opened
by a controller (not shown), the system 26 allows cleaning of the
canister 12 in compliance with EVAP emission regulations.
Pressurized exhaust air flow 38, which is at a temperature above
ambient conditions, may be mixed in mixing structure 32 with
ambient air that passes through vent valve 22 and the output air
flow 33 enters the canister 12. Hydrocarbons in the canister 12 are
purged through the purge valve 14 and are consumed in the engine
20'. This use of exhaust air flow 38 advantageously provides a
higher temperature for the purging air flow 33 so as to recover
more of the hydrocarbons in the canister 12 and reduce the heel.
This increases the storage capacity for a given amount of charcoal
in the canister 12. Increasing the storage capacity of the canister
12 allows smaller canisters to be used, or provides more robustness
for usage of ethanol fuels which have been shown to increase the
heel in a canister 12.
[0016] Although the mixing structure 32 is provided, it can be
appreciated that instead of providing the mixing structure 32, the
ambient air from valve 22 and the exhaust air flow 38 from valve 34
can be mixed in the canister 12. Temperature sensors (not shown)
can be provided at least downstream of the output air flow 33 to
ensure that the output air flow 33 is at a desired temperature.
[0017] On turbocharged engines, the manifold vacuum used in
conventional EVAP systems is not available during turbocharger
operation, but the use of the pressure of the exhaust air flow 38
allows the canister 12 to be purged even with the turbocharger 28
operating.
[0018] On conventional (non-turbocharged) systems, the most
manifold vacuum is available at low engine speeds when total fuel
required is low and the EVAP fuel can be a significant portion. The
uncertainty of fuel content in the EVAP flow creates extra
calibration effort to avoid engine stumble and stall. The
pressurized system 26 can purge the canister 12 at high engine
speeds (when no vacuum source is available) which allows easier
calibration and lower vehicle development costs.
[0019] The foregoing preferred embodiments have been shown and
described for the purposes of illustrating the structural and
functional principles of the present invention, as well as
illustrating the methods of employing the preferred embodiments and
are subject to change without departing from such principles.
Therefore, this invention includes all modifications encompassed
within the spirit of the following claims.
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